Compact coupler plug, particularly for a planar broadband lambda probe, in which single-conductor seals are prevented from being lost

ABSTRACT

To make possible a very small and compact embodiment of a coupler plug  1 , especially for use for a planar broadband lambda probe having an adjusting unit  6 , the coupler plug  1  being essentially made up of a housing  2 , namely a base element  3  and a cover element  4  as well as seals  10 , which seal off the interior of the housing from the exterior, and having an adjusting unit  6  for a probe, especially a planar broadband lambda probe, which is mounted in the coupler plug  1  or outside the coupler plug via a further contact element, it is proposed according to the present invention that the cover element  4  and the seals  10  constitute a single part and therefore along with the cover element  4  constitute one non-detachable unit.  
     In this manner, it is assured that the seals  10 , which enclose the individual wires  8  that emerge from the coupler plug  1 , can be mounted in one single working or assembly step.

[0001] The present invention relates to a coupler plug, in particularfor a planar lambda probe, made up of a housing, namely a base elementand a cover element as well as electrical components that can beinserted and fixed in the housing, and an adjusting element for a probe,especially a planar broadband lambda probe, which is mounted in thecoupler plug or outside the coupler plug via a further contact element,as well as at least one seal, which seals off from the interior of thehousing the individual wires that emerge from the coupler plug.

BACKGROUND INFORMATION

[0002] Coupler plugs of the aforementioned type are usually designed forthe connection between a cable harness plug and a lambda probe, theconnections in the coupler plug being provided for adjustment, signal,and/or heating of the probe. The lambda probe and the lambda control, inconnection with three-way catalytic converters, represent today aneffective method for cleaning exhaust emissions. The lambda probe,which, for example, can be inserted into an exhaust system, includes asensor for determining the oxygen content in the exhaust gas.

[0003] The residual oxygen content is well-suited for use as a measuredquantity, and it regulates the air-fuel ratio, because it indicatesprecisely whether the air-fuel mixture is being completely combusted.

[0004] In this context, the lambda probe supplies a voltage signal,which represents the momentary value of the mixture composition andwhich follows the mixture changes. The fuel supply to the engine iscontrolled by a carburation system in accordance with the signal fromthe lambda probe in such a way that a stochiometric air-fuel ratio λ=1is achieved. Heated or unheated probes are used in accordance with thedesign of the exhaust gas system and the conditions in which they areused. Outside the field of motor vehicles, other applications of thelambda probe include, e.g., regulating gas motors or oil/gas burners.

[0005] In particular, broadband lambda probes are designed in modularform and, in combination with planar technology, facilitate theintegration of a plurality of functions. They usually have functionallayers, which are made up of a porous protective layer, an externalelectrode, a sensor film, an internal electrode, a reference gas channelfilm, an insulation layer, a heating element, a heating film, a resistoror adjustment element, and connection contacts.

[0006] Because broadband lambda probes are made up of the combination ofa nernet concentration cell (=sensor cell) and a pump cell thattransports oxygen ions, it can measure very precisely, not only in thestochiometric point at λ=1, but also in the lean and rich mixtureranges.

[0007] Every probe must be individually adjusted. For this purpose, theprobe has a built-in resistor (“mini-hybrid”). The adjustment, which isadvantageously performed using a laser beam, is made by properlyablating the resistance layer made up of a ceramic substrate, therebyinducing a change in the resistance, so that an adjustment follows.

[0008] One specific embodiment provides for the adjustment unit, i.e.,the resistor, to be mounted directly at the probe. A further exemplaryembodiment provides for the resistor to be accommodated externally, forexample, on a cable harness plug that is coupled to the probe.

[0009] Heretofore, the adjustment has been carried out by transportingthe housing of the coupler plug, in which the resistor is embedded, tothe adjustment station without the cover element. After the appropriatelaser processing for the adjustment, the cover element was mounted at afurther assembly station.

[0010] To prevent the ingress of humidity, contamination or the likeinto the coupler plug, and to assure that the appropriate atmosphereprevails within the coupler plug, the cover element has additionalseals. During assembly, the seals themselves are mounted on the coverelement or on the base element in a selective fashion and as a functionof the corresponding application case. The seals are made of arubber-like material, which can be compressed or expanded, to assurethat the seal completely and sealingly contacts both the individualwires emerging from the housing as well as the housing, or coverelement.

[0011] In addition, pressure equalizing elements are mounted on thehousing of the coupler plug.

DISADVANTAGES OF THE RELATED ART

[0012] One disadvantage of the design of the coupler plug discussed herecan be seen, in particular, in that it is necessary to manufacture bothseals as well as cover elements in two distinct working processes, theparts having essentially the same function, namely to seal off theinterior of the housing from the environment of a cable harness plug.

[0013] A further disadvantage of the design lies in the fact thatadditional working and assembly steps are necessary to install theseals, which seal off the housing interior from its surroundingenvironment. In this context, it is necessary in the assembly process topay special attention to the fact that the seal sealingly contacts boththe individual wires emerging from the housing as well as the coverelement, i.e., the housing itself.

[0014] In assembling a cable harness plug of this type, there is alsothe danger that seals that are important for the functioning of thecable harness plug can be forgotten.

OBJECT OF THE INVENTION

[0015] The object of the present invention is to refine an embodiment ofthe coupler plug that is provided especially for a planar broadbandlambda probe, so as to make it very easy to assemble.

ACHIEVEMENT OF THE OBJECTIVE

[0016] The objective is achieved in that the cover element and the sealconstitute a single piece.

ADVANTAGES OF THE INVENTION

[0017] One essential advantage of the present invention is that thecoupler plug it proposes is designed to be a single piece, so that asimple assembly of the cover element on the base element is assuredwithout having to additionally preassemble the necessary seals.

[0018] The cover element is advantageously made of PBT (polybutyleneterephthalt) or a similar material, and the seals are injection-moldeddirectly onto the cover element.

[0019] It can alternatively be provided that the seals are mounted onthe cover element before it is assembled. A retainer prevents the sealfrom detaching from the cover element, for example, when the coverelement is being stored.

[0020] A further advantageous exemplary embodiment of the presentinvention is provided for in that the cover element is made so as to betransparent. In this way, it is possible to determine whether the sealshave the correct shape and position in contacting both the base elementas well as the individual wires extending from the base element.

[0021] Further advantageous embodiments are derived from thedescriptions, claims, and drawings below.

DRAWINGS

[0022] The following are the contents:

[0023]FIG. 1 depicts a side view of the coupler plug according to thepresent invention, having a closed cover;

[0024]FIG. 2 depicts a rear view of the coupler plug according to FIG.1;

[0025]FIG. 3 depicts a top view of the coupler plug according to FIG. 1;

[0026]FIG. 4 depicts a cutaway view of the coupler plug according toFIG. 1.

DESCRIPTION OF AN EXEMPLARY EMBODIMENT

[0027] Coupler plug 1, depicted in FIGS. 1 through 4, is a type of plugthat is made up of a housing 2 that is composed of a base element 3 anda cover element 4.

[0028] On base element 3, an adjustment unit 6 is mounted in a holdingdevice 5, the adjustment unit in turn being connected via electricalcontact elements 7 to the lambda probe (not depicted in greater detailin the drawings), that is connected via a connecting element in the formof one or a plurality of individual wires 8.

[0029] Electrical contact elements 7 are made up of metal strips thatare shaped like printed circuit traces, which, in the area of couplingpotential 9 of coupler plug 1, terminate in their one side.

[0030] Adjustment unit 6 is guided by guide elements (not depicted ingreater detail in the drawings), that are configured as part of theholding device 5 and that are mostly mounted on base element 3, and itis held in position by electrical contact elements 7.

[0031] Advantageously, coupler plug 1 on its periphery has grooves 14,which permit a coupler plug 1 to be inserted in holders that areprovided for this purpose.

[0032] In addition, holding and fixing elements 15 are configured inbase element 2, as depicted in FIGS. 1, 2, and 4, the elements making itpossible to mount coupler plug 1 on electrical leads 16.

[0033] For this purpose, holding and fixing element 15 is configuredlike a clip, so that coupler plug 1, in the open position of holdingelement 15, can be plugged into a cable wire (electrical leads 16), andcan then be sealed by a further motion.

[0034] In this manner, it is possible to secure the coupler plug, forexample, on a motor (holder).

[0035] In addition, on cover element 4, seals 10 are arranged which, inthe mounted state as depicted in the Figures, sealingly contact bothcover element 4 as well as housing 2. In addition, individual wires 8are sealingly enclosed, so that the interior of housing 2 is completelysealed off from the exterior.

[0036] Seals 10 are mounted on cover element 4 in a permanent fashion,and during assembly are mounted on base element 3 along with coverelement 4.

[0037] Due to its small exterior dimensions, it is also possible toaccommodate the coupler plug in a grooved tube.

What is claimed is:
 1. A coupler plug (1), especially for a planarlambda probe, made up of a housing (2), namely a base element (3) and acover element (4), as well as electrical components that can be insertedand fixed in the housing; and an adjusting element (6) for a probe,especially a planar broadband lambda probe, which is to be mounted inthe coupler plug (1) or outside the coupler plug via a further contactelement, as well as at least one seal (10), which seals off from theinterior of the housing (2), the individual wires that emerge from thecoupler plug (1), wherein the cover element (4) and the seal (10)constitute a single part.
 2. The coupler plug as recited in claim 1,wherein the seal (10) is injection-molded onto the cover element (4). 3.The coupler plug as recited in claim 1, wherein the seal (10) can benon-detachably connected to the cover element (4).
 4. The coupler plugas recited in claim 3, wherein the seal (10) can be clipped onto thecover element (4).